Ultra-broadband terahertz absorption using bi-metasurfaces based multiplexed resonances

Area of Science:

• Optics and Photonics
• Metamaterials
• Terahertz Technology

Background:

• Metasurfaces offer unique electromagnetic properties.
• Achieving ultra-broadband absorption in terahertz frequencies is challenging.
• Existing absorbers often have limited bandwidth or efficiency.

Purpose of the Study:

• To design and demonstrate an ultra-broadband terahertz absorber.
• To achieve high absorption over a wide frequency range.
• To explore the potential of bi-metasurfaces for terahertz detection.

Main Methods:

• Fabrication of a bi-metasurface absorber with two stacked metasurfaces.
• Utilizing multiplexed cross resonators with varying geometries and sizes.
• Employing a metallic ground plane and parylene dielectric layers.
• Experimental characterization of the absorption spectrum.

Main Results:

• Demonstrated an ultra-broadband terahertz absorber with absorption >50% over a 4.46 THz bandwidth.
• The bottom metasurface achieved 3.80 THz bandwidth at high frequencies.
• The top metasurface and Salisbury screen provided low-frequency absorption, bridging the bands.
• Achieved a full width at half maxima (FWHM) of 97.7%.

Conclusions:

• The proposed bi-metasurface absorber enables ultra-broadband absorption in the terahertz regime.
• The design effectively combines multiple absorption mechanisms for wideband performance.
• This absorber is a promising candidate for terahertz broadband detection applications.